JEFFERSONVILLE — A harsh winter that pushed the school year into June and rainy weather early this summer have put a dent in revenue at Southern Indiana tourism attractions.

Parks, caves and historic sites are reporting the number of visitors has dropped from last year, and many say the late start to summer vacation is the main culprit.

“The school year has changed the face of summer tourism,” Rand Heazlitt, Harrison County’s parks director, told the Courier-Journal in Louisville. “The landscape is just changing.”

Many Indiana students stayed in school during the first week in June because of harsh weather that forced districts to close in January and February. A conversion to a balanced calendar in some districts will send students back to class earlier, further shortening their time off.

“It seemed like school just got out before it’s going back in two weeks,” said Jeremy Yakeley, executive director of the Harrison County Convention and Visitors Bureau.

Harrison County parks have seen admissions drop 15 to 20 percent from last summer, Heazlitt said. Revenue also is down at the three show caves in Harrison and Crawford counties — Indiana Caverns, Squire Boone and Marengo — and at four historic sites operated by the Indiana State Museum.

Those sites, in Corydon, New Albany, Bloomington and Madison, saw combined attendance drop by nearly 8,600 visits from the same period last year, said Laura Minzes, deputy director of historic sites. They were the only losses among historic sites statewide this summer.

Gary Roberson, co-owner of Indiana Caverns, the new attraction that opened last summer south of Corydon, said business “has never totally recovered” from the bad winter.

Some tourism leaders hope the rest of the summer shows improvement. Holiday World had a record July 4 weekend, and Roberson said things are looking up at Indiana Caverns.

But Jim Epperson, executive director of the Clark-Floyd Counties Convention and Tourism Bureau, said the situation illustrates the concerns tourism officials have long raised about the impact of shorter summer breaks on local businesses and economic development.

“As a parent and a tourism industry person, I’ve been against (the new school calendar) all along,” he said.

Parents have organized Save Our Summer groups during the past decade to lobby state lawmakers to bar schools from starting until late August. But the efforts have drawn little support.

Heazlitt said tourism officials will need to be smarter about capturing business through online reservation systems and restructuring to boost fees when an amenity, such as Harrison’s campgrounds, is showing an uptick.